Forest Soil, Long After Most Acidic Rain, Remains Acidichttp://apocadocs.com/s.pl?1231816781
Following the Clean Air Act Amendments of 1970 and 1990 acidic deposition in North America has declined significantly since its peak in 1973. Consequently, research has shifted from studying the effects of acidic deposition to the recovery of these aquatic and terrestrial ecosystems.... The researchers believe that the observed trend in soil acidification is likely to continue until acidic inputs decline to the point where soil base cation pools are sufficient to neutralize them. Warby concluded, "Until then we are likely to see the continued sluggish chemical recovery of surface waters and a continuing threat to the health of forests, with additional declines in base status likely to increase the number of sites exhibiting lower forest productivity and or vulnerability to winter injury."